This invention relates generally to interconnection systems and more specifically to an apparatus for protecting mobile transceivers from the application of improper polarity on the power terminals.
The literal explosion in the use of mobile transceivers such as citizens band radios has brought into the field many people who have no previous experience with electronics. These newcomers, accustomed as they are to the use of household alternating current power, have little or no appreciation of the significance of polarity in electronic devices which are operated from batteries. Their entire experience to "plugging-in" appliances completely negates any instructions accompanying the mobile transceiver. In the house, it never matters which way one plugs in a power cord, so it is likely that the instructions on connecting a mobile radio will not be read until after the unit is installed and is found not to operate. By that time, given the odds of one out of two choices being wrong, the transceiver is likely to be severely damaged.
This problem is aggravated by the tendency of many mobile operators to move their units from one vehicle to another, again with no appreciation of the fact that vehicles are manufactured with both positive grounds and negative grounds. The result is that a trucker, who has had the use of his citizens band radio is his truck and has decided to arrange it detachably so that it can also be used in his automobile or another truck, is likely to damage the radio in attempting to use it in another vehicle because of a change in vehicle polarity relative to the mounting brackets.
This substantial likelihood of damage to expensive equipment points out the requirement for an inexpensive protective system which operates automatically to both protect the transceiver from incorrect polarity and also to place properly polarized power on the transceiver so that it will operate without further reconnection, regardless of the polarity of the original connection.